Bump mini_magick from 4.5.1 to 4.9.4

Bumps [mini_magick](https://github.com/minimagick/minimagick) from 4.5.1 to 4.9.4.
- [Release notes](https://github.com/minimagick/minimagick/releases)
- [Commits](minimagick/minimagick@v4.5.1...v4.9.4)

---
updated-dependencies:
- dependency-name: mini_magick
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Gemfile.lock

@@ -193,7 +193,7 @@ GEM
     mime-types (3.4.1)
       mime-types-data (~> 3.2015)
     mime-types-data (3.2023.0218.1)
-    mini_magick (4.5.1)
+    mini_magick (4.9.4)
     mini_mime (1.1.2)
     mini_portile2 (2.1.0)
     minitest (5.15.0)